Current internal combustion engine is constructed to burn liquid fuels, such as diesel or gasoline but not coal-mine methane. Coal-mine methane is basically a mixture of methane (CH4) and air. The drained methane from underground coalmines is at concentrations ranging from 6% to 80%, and is generally called “methane”. Methane is distinguished as “High-Concentration Methane (HCM)”, when the methane concentration is above or equal to 30%; or as “Low-Concentration Methane (LCM)”, when its concentration is less than 30%. At present, applicable technologies for HCM are available, where it is utilized to generate electricity or to supply residential households, however, effective technology for application of LCM has not yet been established. Currently, LCM is not utilized and instead is released directly into the atmosphere, resulting in environmental pollution and energy waste.